JP5541249B2 - PON system, station side apparatus, operation method thereof, and access control apparatus - Google Patents

Description

  The present invention relates to a PON (Passive Optical Network) system in which a station-side device and a plurality of home-side devices are connected through a communication line having a tree structure, a station-side device that is a component of the system, and an operation of the station-side device The present invention relates to a method and an access control apparatus.

The PON system is an optical communication system that performs optical branching in a P2MP (Point to Multi Point) connection mode without power, and includes a station-side device and a single-core optical fiber network that branches from the station-side device as a vertex. It includes a tree-structured PON line and a plurality of home-side devices connected to the ends of the branched optical fibers (see, for example, Patent Documents 1 to 3).
In this PON system, a NRZ (Non-Return to Zero) optical signal obtained by directly or externally modulating a light source such as a semiconductor laser is transmitted, and predetermined information is transmitted and received.

In such a PON system, a downstream frame composed of an optical signal transmitted from a station side device is transmitted to each home side device in a broadcast format. The home side apparatus notifies the logical link identifier (for example, LLID in the case of PON defined in IEEE Std 802.3 ^TM- 2008), which is notified from the station side apparatus during discovery and is included in the preamble of the downstream frame. Referring to LLID as a representative example), a downlink frame addressed to the own station (including a case of multicast) is received, and the other downlink frames are discarded.
On the contrary, for the upstream frame composed of the optical signal transmitted from each home side apparatus to the PON line, the station side apparatus performs multiple access control by time division for each LLID in order to prevent collision. Accordingly, the station-side device receives the upstream optical signal from each home-side device in a burst manner.

JP 2004-289780 A JP 2007-174364 A JP 2007-243284 A

The station-side device of the PON system includes an access control unit (hereinafter also referred to as “access control device”) that performs multiple access control of uplink frames in the PON section based on an access control protocol. For example, in the case of PON defined by IEEE Std 802.3 ^TM- 2008 and IEEE Std 802.3av ^TM- 2009, MPCP (MultiPoint Control Protocol) corresponds to the above access control protocol.
This access control device is usually configured by mounting a plurality of LSIs (Large Scale Integrated Circuits) on a control board, and is configured with a programmable logic circuit (Field-Programmable Gate Array: FPGA) or a microprocessor (Micro-Processing Unit). : MPU) according to a computer program stored in advance in the memory.

Therefore, in order to add or change functions to the access control device (hereinafter collectively referred to as “changes”), it is necessary to update a computer program executed by a logic circuit or a microprocessor.
However, updating the computer program usually includes a procedure to reset the processor of the access control device to the initial state and then restart it with a later function, etc., so the restart from the reset is completed During the update work up to this point, there was a problem that the data transfer between the host network and the PON line had to be stopped.

The communication interruption time associated with such an update is not short enough to maintain the communication quality required for transmission of telephones and video signals. For example, the communication interruption time is usually longer than the timeout time (1 second) defined by MPCP. .
For this reason, traditionally, in order to minimize the damage caused by communication interruptions such as telephone calls, operators of telecommunications carriers have updated computer programs in anticipation of timing in the midnight hours when traffic is relatively low. It has been a lot of work to change the functions of the access control device.

  Also, in the conventional station side device, the access control device is connected to the PON side optical transmission / reception unit in a one-to-one correspondence, so even if the traffic on the PON line is small and the data transfer amount by the station side device is small, There is also a drawback in that the access control device must always be operated, and the power consumption of the access control device cannot be reduced.

  In view of such a conventional problem, the present invention causes an access control unit to perform uplink multiple access control for a plurality of PON lines in a station side apparatus to which a plurality of PON lines are connected, and the remaining access control units It is a first object of the present invention to enable a degenerate mode that does not allow communication frames to communicate with each other.

A second object of the present invention is to make it possible to update the computer program for the access control unit without stopping the data transfer in the station side device.
Furthermore, a third object of the present invention is to reduce the power consumption in the access control unit of the station side device.

  (1) A station-side apparatus of the present invention is a station-side apparatus that forms a PON system with a plurality of home-side apparatuses, and includes a first optical transceiver that can be connected to a first PON line, and a second PON A second optical transceiver that can be connected to a line; a normal line control that is an uplink multiple access control for the first PON line; and a plurality of lines that are the uplink multiple access control for the first and second PON lines. A first access control unit capable of executing control, a second access control unit capable of executing normal line control, which is the uplink multiple access control for the second PON line, and the upper side of both access control units A lower switch provided between the access control unit and the optical transmission / reception unit, and a degeneration control capable of switching both the switches as shown in (a) and (b) below. Department and Characterized in that it comprises a.

(A) The output destinations of the downstream frames to the first and second PON lines input to the upper switch are concentrated on the first access control unit, and the downstream frames input to the lower switch from the first access control unit The output destination is distributed to the first and second optical transmission / reception units.
(B) Concentrate output destinations of uplink frames input from the first and second optical transmission / reception units to the lower switch in the first access control unit.

  In the present specification, the “first access control unit” refers to the plurality of lines that simultaneously perform uplink multiple access control for the other second PON lines in addition to the first PON line that is normally managed by itself. This refers to an access control unit that can be controlled (an access control unit that can be in an “active” state, which will be described later). The “second access control unit” means that the first access control unit performs the multi-line control. This means an access control unit (an access control unit that can be in a “standby” state, which will be described later) that prevents communication frames from communicating.

According to the station side apparatus of the present invention, when the degeneration control unit switches both switches as in the above (a) and (b), the first access control unit executes the multi-line control, and as a result, The communication frame cannot be communicated with the second access control unit.
For this reason, in the station side apparatus to which the first and second PON lines are connected, a plurality of PON lines are assigned to a smaller number of first access control units, and communication frames are transmitted to the remaining second access control units. A degenerate mode that does not allow communication can be performed, and the first object is achieved.

(2) In the station side apparatus of this invention, it is preferable that the said degeneracy control part can further switch both said switches like following (c) and (d).
(C) The output destination of the downstream frame to the first and second PON lines input to the upper switch is distributed to the first and second access control units, and the first and second access control units are transferred to the lower switch. The output destinations of the input downlink frames are set in the first and second optical transmission / reception units, respectively.
(D) Cause the first and second access control units to set the output destinations of the upstream frames input from the first and second optical transmission / reception units to the lower switch.

In this case, when the degeneration control unit switches both switches as in (c) and (d) above, the first access control unit performs normal line control on the first PON line, and the second access The control unit executes normal line control for the second PON line.
For this reason, it is possible to return the station side device operated in the degenerate mode to the normal mode in which the first and second access control units both perform the normal line control.

(3) In the station apparatus of the present invention, the first access control unit sets a logical link identifier for the first PON line and a logical link identifier for the second PON line as values. It is necessary to perform the multiple line control using a logical link identifier held in the management table.
The reason is that, in PON, home-side devices are identified by logical link identifiers, and therefore, if the logical link identifiers are duplicated in each PON line, appropriate uplink multiple access control cannot be performed when performing multiple line control. It is.

As a method for managing the first link control unit so that the logical link identifier values do not overlap even in the case of multi-line control, the first and second access control units are performing normal line control. The logical link identifiers are notified to each other, or the first access control unit uses an odd number and the second access control unit uses an even number. There is a way to do it.
Alternatively, the logic of the second access control unit when shifting from the state in which the first and second access control units respectively perform normal line control to the state in which only the first access control unit performs multi-line control (degenerate state). There is also a method in which the link is temporarily disconnected and the logical link is established again by the first access control unit.

(4) On the other hand, in the PON, the station side device manages information such as a MAC address and RTT (Round Trip Time) for each logical link identifier. Consider it, disconnect the logical link, and redo the discovery.
In the PON, the station side device records the count value (time) of the internal clock as a time stamp at the time of transmission of the control frame to synchronize the time with the home side device. Accordingly, the home side device disconnects the logical link when the time maintained by the local station and the time stamp value notified from the station side device are different from each other by a predetermined value or more.

  Therefore, in the station side device of the present invention, the degeneration control unit degenerates the operation mode of the station side device only by the first access control unit sharing only the value of the logical link identifier with the second access control unit. When switching to the mode, all the logical links with the home side devices belonging to the second PON line are temporarily disconnected, and it becomes necessary to redo all the discovery with those home side devices from the beginning, and communication is interrupted accordingly. The time to become longer.

Therefore, in order to prevent the logical link from being automatically disconnected by switching to the degeneration mode, the previous first access control unit transmits information necessary for maintaining the logical link to the second access control. It is preferable that the logical line identifier is acquired from the storage unit and stored in advance in the management table, and the multiple line control is performed using the stored information.
In this way, the information required to maintain the logical link (such as the MAC address and RTT) can be grasped by the first access control unit from the beginning of the multiple line control, and the information is unknown. Automatic disconnection of the logical link can be prevented beforehand.

(5) (6) For the same reason, the first access control unit uses a clock synchronized with the second access control unit, and the time used by the second access control unit. It is preferable to perform the multiple line control using a time stamp whose deviation from a stamp is a predetermined value or less.
In this case, the first access control unit uses a clock synchronized with the second access control unit, and uses a type stamp whose deviation from the type stamp used by the second access control unit is a predetermined value or less. time stamp access control unit notifies the optical network unit belonging to the second PON line is generally consistent with the case of the second access control unit.

Therefore, the home side device belonging to the second PON line is prevented from automatically disconnecting the logical link due to being notified of a time stamp that is not within the range of time stamp values allowed before and after switching of the degeneration mode. it can.
It is not always essential that the first and second access control units maintain substantially the same time stamp, and the first access control unit uses a clock synchronized with the second access control unit. Just be fine. Even in this case, when different time stamps are notified from different access control units at the time of switching, it is possible to maintain the logical link of the home side device by adopting a rule that the home side device does not disconnect the logical link. it can.

(7) However, in the station side apparatus of the present invention, disconnection of the logical link accompanying switching of both switches by the degeneration control unit may be permitted. In this case, the first and second access control units may cancel the registration of the logical link identifier in which the control subject of the uplink multiple access control changes before and after the degeneration control unit switches the both switches. preferable.
In this way, the reduced mode can be realized relatively easily as compared with the case where the multiple line control is performed so as to prevent the logical link from being automatically disconnected by switching to the reduced mode. it can.

(8) In the station-side apparatus of the present invention, the first access control unit uses the first or second optical transmission / reception for each discovery process as an input source of an upstream frame in the lower switch in the multi-line control. It is preferable that the registration sequence of the home-side apparatus is executed by being fixed to any of the units.
In this case, it is possible to appropriately join a new home apparatus to the PON even during the period when the first access control unit performs the multiple line control. Further, the station side device can grasp whether the home side device newly joined to the PON is the home side device belonging to the first or second PON line.

(9) Moreover, in the station side apparatus of this invention, the said 1st and 2nd access control part is only the grant whose transmission timing of the upstream frame to permit is before switching of both said switches by the said degeneracy control part. It is preferable to produce.
In this way, an uplink transmission collision caused by the transmission of an uplink frame by the home-side apparatus after the switching of both switches by the grant granted by the first or second access control unit before the switching of both switches has occurred in advance. Can be prevented.

(10) Further, in the station side apparatus of the present invention, the first access control unit is configured such that, in the multi-line control, transmission timings of uplink frames permitted to the home side apparatus belonging to the same PON line are continuous. In addition, it is preferable to schedule the uplink frame.
In this case, when the first access control unit does not consider which PON line the home device belongs to, the number of times the lower switch is switched within a predetermined time is compared with the case where the uplink frame is randomly scheduled. Even if the time overhead associated with switching of the lower switches is not small, the total overhead can be kept relatively small.

(11) The method of the present invention is a method of switching and operating the operation mode of the station side device to which at least two PON lines are connected. The switchable operation modes include the following (x) and (y) Is included.
(X) Normal mode in which the first access control unit performs uplink multiple access control for the first PON line, and the second access control unit performs the uplink multiple access control for the second PON line. (Y) First And a degenerate mode in which the first access control unit performs multi-line control, which is the uplink multiple access control for the second PON line, and does not allow communication frames to be communicated to the second access control unit

  According to the method of the present invention, the above-mentioned (x) and (y) are included as the switchable operation modes of the station side apparatus. Therefore, in the station side apparatus to which at least two PON lines are connected, a plurality of PON lines are connected. It is possible to perform a degenerate mode in which a smaller number of first access control units are assigned and the remaining second access control units do not communicate communication frames. For this reason, the first object is achieved.

(12) In the method of the present invention, it is preferable that a change of the computer program for the programmable component included in the second access control unit and a restart after the change are performed during the degenerate mode.
That is, in the degenerate mode, the first access control unit performs the multiple line control that is the uplink multiple access control for the first and second PON lines, and therefore the computer for the second access control unit during the degenerate mode. If the program is changed and restarted, the computer program can be updated without stopping the data transfer in the station side device. For this reason, the second object of the present invention is achieved.

(13) Also, in the degeneration mode, communication frames are not communicated to the second access control unit, so in the method of the present invention, power supply to the second access control unit is stopped during the degeneration mode period. Or you may decide to suppress.
In this way, it is possible to reduce the power consumption in the access control unit of the station side device as compared to the case where power is supplied to both the first and second access control units as usual. For this reason, the third object is achieved.

(14) On the other hand, in the degenerate mode, the first access control unit performs uplink multiple access control for a larger number of home side devices than in the normal mode. Communication bandwidth decreases.
Therefore, in the method of the present invention, it is preferable that the degenerate mode is executed in a time zone in which traffic on the first and second PON lines is equal to or less than a predetermined value. In this way, it is possible to suppress the decrease in the uplink bandwidth as much as possible as the number of home side devices controlled by the first access control unit increases.

(15) The access control device of the present invention is a control device (same as the “access control unit”) that can be suitably employed in the station-side device of the present invention.
That is, the access control apparatus of the present invention is an access control apparatus that performs uplink multiple access control, and includes a management table that holds a logical link identifier for identifying a home-side apparatus, and a logical link held in the management table A PON control unit that performs the uplink multiple access control using an identifier, and the PON control unit includes a logical link identifier for the first PON line that is normally managed by the PON control unit and other access control. The logical link identifier for the second PON line that is normally managed by the device is held in the management table so that the values do not overlap, and the first and second logical link identifiers are stored using the logical link identifier held in the management table. A plurality of line control which is the uplink multiple access control for the second PON line is performed.

  According to the access control apparatus of the present invention, the PON control unit uses the logical link identifier for the first PON line that is normally managed by itself and the second PON line that is normally managed by another access control apparatus. The logical link identifier is held in the management table so that the values do not overlap, and multiple line control, which is uplink multiple access control for the first and second PON lines, is performed using the logical link identifier held in the management table. As a result, the communication frame does not communicate with other access control devices accommodated in the station side device.

  For this reason, in a station-side device to which a plurality of PON lines are connected, a degenerate mode in which a plurality of PON lines are assigned to the access control apparatus of the present invention and communication frames are not communicated to the other access control apparatuses can be performed. And the first object is achieved.

(16) PON system of the present invention, a plurality of the optical network unit is connected to the front Symbol first and second PON line, how to operate according to any one of the above (11) - (14) And the station side device capable of performing the above.
For this reason, the PON system of this invention has the same effect as the station side apparatus in any one of said (11)-(14).

As described above, according to the present invention, uplink access control for a plurality of PON lines is performed by a smaller number of access control units, so that a degenerate mode in which communication frames are not communicated to the remaining access control units can be executed.
Further, according to the present invention, in the degeneration mode, by updating the computer program for the access control unit that does not communicate with the communication frame, the computer program for the access control unit is not stopped without stopping the data transfer in the station side device. Can be updated.

  Furthermore, according to the present invention, power consumption of the access control unit of the station side device can be reduced by stopping or suppressing the power supply to the access control unit that does not communicate with the communication frame in the degeneration mode.

It is a figure which shows the connection form of the PON system which concerns on embodiment of this invention. It is a block diagram which shows the structure of a station side apparatus. It is a figure which shows the flow of the communication frame in normal mode. It is a figure which shows the flow of the communication frame in a degeneration mode in the case of concentrating access control on the system | strain A side. It is a figure which shows the flow of the communication frame in a degeneration mode in the case of concentrating access control on the system | strain B side. FIG. 10 is a sequence diagram illustrating an example of uplink bandwidth allocation by an active access control unit. It is a sequence diagram which shows another example of the upstream band allocation by an active access control part. It is a figure which shows the connection form of the PON system for showing the modification of a high-order switch. It is a block diagram for showing the modification of a low-order switch.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[PON system connection form]
FIG. 1 is a diagram showing a connection form of a PON system according to an embodiment of the present invention.
As shown in FIG. 1, the PON system of this embodiment includes an optical line terminal (OLT) 1 on the telecommunications carrier side, an optical network unit (ONU) 3 on the home side, Is a connection form (topology) in which the PON lines 4A and 4B have a tree structure.

The optical line termination device 1 on the provider side is composed of an assembly in which a plurality of optical subscriber termination units (OSU: Optical Subscriber Units) 2 are accommodated in a single housing, and PON lines 4A and 4B are connected to the termination panel 2. Each is connected.
Hereinafter, in this embodiment, each optical subscriber termination board 2 or an optical line termination device 1 that is an aggregate thereof is referred to as a “station side device”, and is connected to this station side device via PON lines 4A and 4B. The home-side line termination device 3 is referred to as a “home-side device”. Further, “station side device” may be abbreviated as “OSU” or “OLT”, and “home side device” may be abbreviated as “ONU”.

Two stations of PON lines 4A and 4B are connected to the station side apparatus 2, respectively. These PON lines 4A and 4B are a single-core optical fiber 5 connected to the station side apparatus 2 and a passive optical branching node. An optical coupler 6 and a single-core optical fiber 7 branched from the optical coupler 6 are included.
The optical fiber 7 is branched from the optical coupler 6 by a predetermined number of branches (for example, 32 or 64 branches), and the home-side apparatus 3 is connected to the end thereof. The upper side (left side in FIG. 1) of the station side device 2 communicates with the higher level network, and the lower side (right side in FIG. 1) of each home side device 3 communicates with the lower level network.

As transmission methods in the PON lines 4A and 4B, GE-PON having an uplink / downlink transmission rate of 10G (baud rate is 10.3125 Gbps) and an uplink / downlink transmission rate of 1G (baud rate is 1.25 Gbps). Alternatively, an asymmetric 10G-EPON having a downlink transmission rate of 10G and an uplink transmission rate of 1G can be employed.
For this reason, the station-side device 2 is compatible with both 1G and 10G transmission rates, and the home-side device 3 is composed of a 1GONU, a 10G asymmetric ONU, or a 10G symmetric ONU.

[Configuration of station side equipment]
FIG. 2 is a block diagram showing a configuration of the station side device 2.
As shown in FIG. 2, the station side device 2 includes, in order from the upper side (upper side in FIG. 2) to the lower side, the upper switch 11, access control units 12 </ b> A and 12 </ b> B, the management unit 13, the lower switch 14, and optical transmission / reception. A control unit 15 and optical transmission / reception units 16A and 16B are provided.

In response to controlling the two systems of PON lines 4A and 4B in accordance with MPCP, the station-side device 2 of the present embodiment corresponds to the two optical transmission / reception units 16A and 16B connected to the PON lines 4A and 4B, respectively. 16B and two access control units 12A and 12B.
In the following, “system A” and “system B” may be used as expressions for distinguishing the systems of the PON lines 4A and 4B, the access control units 12A and 12B, and the optical transceivers 16A and 16B from each other.

The upper switch 11 includes an L2 switch connected to the upper side of the access control units 12A and 12B. The upper switch 11 multiplexes the upstream frames transmitted by the access control units 12A and 12B and relays them to the upper network, and separates the downstream frames from the upper network to the PON lines 4A and 4B in the case of unicast frames, If it is not a unicast frame, it is copied as necessary and relayed to each access control unit 12A, 12B.
The upper switch 11 can also return a downstream frame from the upper network to the upper network or return an upstream frame from the access control units 12A and 12B to the access control units 12A and 12B.

The management unit 13 performs management of the station side device 2 and management of the home side device 3 via the access control units 12A and 12B, and includes a management interface 19 and a degeneration control unit 20.
The management interface 19 is connected to a management network, and can receive commands from a telecommunications carrier that is an operator via this network.
In the example of FIG. 2 , the management network is a different network from the host network, but both may be the same network.

The degeneration control unit 20 performs switching of the upper switch 11 and switching of the lower switch 14 via the optical transmission / reception control unit 15 based on an input signal from the management interface 19, details of which will be described later.
The lower switch 14 is connected to the PON side (lower side in FIG. 2) of the access control units 12A and 12B, and includes an L1 switch connected to the upper side of the optical transmission / reception units 16A and 16B. The lower switch 14 has a function of switching a route of an electric signal between the access control units 12A and 12B and the optical transmission / reception units 16A and 16B at a physical layer level.

[Configuration of access controller and optical transceiver]
The access control units 12A and 12B and the optical transmission / reception units 16A and 16B of the present embodiment have the same configuration and function in the system A and the system B, respectively. Therefore, in the following, the configuration and function will be mainly described by taking the system A as an example.
The access control unit 12A includes a control device configured by mounting a plurality of LSIs on a control board, and includes a programmable logic circuit (FPGA) and a microprocessor (MPU). The computer program stored in the memory or the like of the access control unit 12A is described in a hardware description language such as VHDL and Verilog for circuit design of the FPGA, a C language that defines the processing contents performed by the MPU, and the FPGA. And code that has been compiled and processed in accordance with the device structure such as MPU.

As shown in FIG. 2 , the access control unit 12A includes, in order from the upper side to the lower side, the upper side transmission unit 22, the upper side reception unit 23, the relay processing unit 24, the LLID management table 25, the PON control unit 26, A PON side receiving unit 27 and a PON side transmitting unit 28 are provided.
The downstream frame input from the upper switch 11 is received by the upper receiving unit 23 and sent to the relay processing unit 24. The relay processing unit 24 transmits the downstream frame to the PON side transmission unit 28, and the PON side transmission unit 28 inputs the downstream frame to the lower switch 14.

The upstream frame input from the lower switch 14 is received by the PON side receiving unit 27 and sent to the relay processing unit 24 or the PON control unit 26.
If the upstream frame is a data frame, the PON receiving unit 27 passes it to the relay processing unit 24, and if it is a control frame such as an MPCP frame or an OAM frame, passes it to the PON control unit 26. The relay processing unit 24 sends the data frame to the higher-level transmission unit 22, and the higher-level transmission unit inputs the data frame to the higher-level switch 11.

The PON control unit 26 performs predetermined processing according to the nature of the control frame received from the PON side receiving unit 27.
For example, if the received control frame is a register request from the home side device 3 in response to the discovery gate broadcast by itself to the PON lines 4A and 4B, the home side device 3 LLID is determined, a register in which the value of the determined LLID is written is generated, and the register is transmitted to the PON side transmission unit 28 in a downstream manner.

In addition, when the received control frame is a report from the home apparatus 3 corresponding to the normal gate (grant) transmitted by itself, the PON control unit 26 responds to the transmission request amount described therein. Uplink dynamic bandwidth allocation is performed using a predetermined algorithm.
Then, the PON control unit 26 generates a grant addressed to a predetermined LLID in which the transmission permission amount determined as a result of the dynamic band allocation and the uplink transmission timing is described, and causes the PON side transmission unit 28 to transmit the grant to the PON side.

The PON control unit 26 also manages an LLID management table (hereinafter simply referred to as “management table”) 25. The management table 25 includes an LLID for identifying the home device in the entry. The PON control unit 26 holds information necessary for maintaining the logical link for each entry of the LLID. This necessary information includes, for example, the following, but is not limited thereto.
1) Type information of the PON lines 4A and 4B This identification information is information indicating whether the ONU belongs to the system A or the system B.

2) ONU Type Information This type information is information indicating whether the ONU is a 1GONU, a 10G asymmetric ONU, or a 10G symmetric ONU.
3) ONU MAC address 4) ONU RTT information

5) QoS parameter This parameter is a parameter for defining a priority class, a minimum guaranteed bandwidth, and a maximum allowable bandwidth set for the ONU.
6) VLAN mode in the upper network

In the present embodiment, the PON control units 26 of the system A and the system B can communicate with each other via the relay processing unit 24, the higher-level transmission / reception units 22 and 23, and the higher-level switch 11 or via a control line (not shown). It is.
The PON control unit 26 of the system A determines the LLID used by the PON control unit 26 of the system B so as not to overlap with the value of the LLID used by the system B PON, and uses it in both the system A and the system B. The management table 25 holds the LLID and the necessary information corresponding thereto. However, as will be described later, such a determination is unnecessary in the case of an implementation that allows the system B logical link to be disconnected once at the time of transition to the degenerate mode.

In addition, the method of notifying each other of LLIDs may be notified every time a logical link is established or disconnected, or may be notified collectively before switching the operation mode related to degeneration. The uniqueness of the LLID between the system A and the system B is used not only by the method of notifying each other between the PON control units 26 of the system A and the system B but also by the PON control units 26 of the system A and the system B. It is also possible to secure the LLID numerical range by a method of dividing in advance.
That is, for example, an odd number is used in the system A, an even number is used in the system B, a value incremented from 0 is used in the system A, and a value decremented from a predetermined value is used in the system B. By separating the two, it is possible to prevent duplication of LLID used in the system A and the system B.

The PON control units 26 of the system A and the system B are operated by the same clock generator (not shown) provided in the station side device 2, and the time (time stamp) counted by this clock generator is used. Also grasp each other by the above communication.
The PON control unit 26 of the system A compares the time stamp notified from the PON control unit 26 of the system B with its own PON counter. The PON control unit 26 of the system A determines whether or not the time difference between them is a predetermined value (for example, 128 ns) or less, and if it exceeds that, the own counter is set to the system B or the system B side Notify the counter to match.

The optical transmission / reception unit 16A includes a known optical transceiver and includes an optical reception unit 30, an optical transmission unit 31, and a multiplexing / demultiplexing unit 32 therein. The optical receiver 30 is composed of a light receiving element such as an avalanche photodiode, and the optical transmitter 31 is composed of a light emitting element such as a laser diode.
The upstream optical signal from the PON line 4A is received by the optical receiving unit 30 through the multiplexing / demultiplexing unit 32. The optical receiving unit 30 converts the received upstream optical signal into an electrical signal and inputs the electrical signal to the lower switch 14. The downstream electrical signal from the lower switch 14 is converted into an optical signal by the optical transmission unit 31, and this downstream optical signal is transmitted to the PON line 4 </ b> A through the multiplexing / demultiplexing unit 32.

The degeneration control unit 20 outputs a control signal for switching the switch to the upper switch 11 and the optical transmission / reception control unit 15 based on a command from the operator received via the management network.
Further, the optical transmission / reception control unit 15 switches the lower switch 14 based on the control signal from the degeneration control unit 20 and the control signal from the PON control unit 26 of the system A or the system B, and the optical transmission / reception unit 16A, It performs reception control for the optical receiver 30 in 16B. This reception control is a control that adapts the reception status of the optical receiver 30 (for example, selection or reset of a reception amplifier circuit, a clock recovery circuit, a decoding circuit, etc. according to the transmission rate) in accordance with the next upstream burst reception. is there.

[Switch control by the degeneration control unit]
FIG. 3 is a diagram showing the flow of communication frames in the normal mode. 4 is a diagram showing a flow of communication frames in the degeneration mode when the access control is concentrated on the system A side, and FIG. 5 is a diagram in the degeneration mode when the access control is concentrated on the system B side. It is a figure which shows the flow of a communication frame.

3 to 5, an arrow indicating a connection between the upper switch 11 and the upper network is drawn with a single line, but this does not mean that the physical connection is one. . Also, it does not mean that the connection destination of the physical connection is one place, and there may be a plurality of physical connections from the upper switch 11 to the upper network, and the connection destination is a plurality of upper devices. is there.
Hereinafter, the contents of the switch control performed by the degeneration control unit 20 will be described with reference to FIGS.

When the command received from the management interface 19 is the “normal mode”, the degeneration control unit 20 sets the routes of both switches 11 and 14 as shown in FIG. The setting of this route will be described as being divided into an upstream frame and a downstream frame as follows.
S1) The output destination of the downstream frame to the PON lines 4A and 4B of the system A and the system B input to the upper switch 11 is distributed to the access control units 12A and 12B of the system A and the system B.
Note that the output destination in this case is determined based on information included in the downstream frame, for example, a VLAN number or a destination MAC address. When the downstream frame to the PON lines 4A and 4B of the system A and the system B is a unicast frame, the frame is transferred to either the PON lines 4A or 4B of the system A or the system B, and the downstream frame is not a unicast frame Is transferred to one of the PON lines 4A and 4B, or transferred to both the PON lines 4A and 4B of the system A and the system B as necessary.

S2) The output destinations of the downstream frames input from the access control units 12A and 12B of the system A and the system B to the lower switch 14 are set in the optical transmission / reception units 16A and 16B of the system A and the system B, respectively.
S3) The output destinations of the upstream frames input to the lower switch 14 from the optical transmission / reception units 16A and 16B of the system A and the system B are set in the access control units 12A and 12B of the system A and the system B, respectively.

Thus, in the normal mode, the access control units 12A and 12B and the optical transmission / reception units 16A and 16B of the same systems A and B are connected in a one-to-one correspondence with respect to both uplink and downlink.
Accordingly, in this normal mode, the access control unit 12A of the system A performs uplink multiple access control (hereinafter referred to as “normal line control”) for one PON line 4A that is normally managed by the system A, and Similarly, the access control unit 12B also performs normal line control that is uplink multiple access control for one PON line 4B that is normally managed by the access control unit 12B.

When the command received from the management interface 19 is the “degeneration mode” in which the access control is concentrated on the system A side, the degeneration control unit 20 sets the routes of both switches 11 and 14 as shown in FIG. The setting of this route will be described as being divided into an upstream frame and a downstream frame as follows.
S4) The output destinations of the downstream frames to the PON lines 4A and 4B of the system A and the system B input to the upper switch 11 are concentrated on the access control unit 12A of the system A.

S5) The output destination of the downstream frame input to the lower switch 14 from the access control unit 12A of the system A is distributed to the optical transmission / reception units 16A and 16B of the system A and the system B.
S6) The output destination of the upstream frame input to the lower switch 14 from the optical transmission / reception units 16A and 16B of the system A and the system B is subjected to time division multiplexing control for the lower switch 14, and the access control unit 12A of the system A To focus on.

  More specifically, when the access control unit 12A that communicates data in the degeneration mode is defined as "active" and the access control unit 12B that does not communicate data in the degeneration mode is defined as "standby", the lower switch 14 performs active access control. The downstream frames received from the PON side transmission unit 28 of the unit 12A are copied and input to the optical transmission units 31 of the optical transmission / reception units 16A and 16B of the systems A and B, respectively.

The lower switch 14 time-division-multiplexes the upstream frames from the optical receivers 30 of the optical transceivers 16A and 16B of the systems A and B to the PON-side receiver 27 of the active access controller 12A. input.
At this time, the PON control unit 26 of the active access control unit 12A ensures that the upstream burst signal received from each of the PON lines 4A and 4B via the optical transmission / reception units 16A and 16B is not lost in the lower switch 14. In addition, it instructs the optical transmission / reception control unit 15 on the switching timing based on the transmission timing that it grants to the home device 3.

As described above, in the degeneration mode of FIG. 4, the degeneration control unit 20 controls the switches 11 and 14 as described above, so that the active access control unit 12A has the PON lines 4A and 4B of both systems A and B. Uplink multiple access control (hereinafter referred to as “multiple line control”) is performed.
As a result, the standby access control unit 12B is in a non-communication state in which the upstream and downstream frames are not input from both the switches 11 and 14 and the communication frame does not communicate.

Further, when the command received from the management interface 19 is the “degeneration mode” in which the access control is concentrated on the system B side, the degeneration control unit 20 sets the routes of both switches 11 and 14 as shown in FIG. To do. The setting of this route will be described as being divided into an upstream frame and a downstream frame as follows.
S7) The downstream frame output destinations to the PON lines 4A and 4B of the system A and the system B input to the upper switch 11 are concentrated on the access control unit 12B of the system B.

S8) The output destinations of the downlink frames input from the access control unit 12B of the system B to the lower switch 14 are distributed to the optical transmission / reception units 16A and 16B of the system A and the system B.
S9) The output destination of the upstream frame input to the lower switch 14 from the optical transmission / reception units 16A and 16B of the system A and the system B is subjected to time division multiplexing control for the lower switch 14, and the access control unit 12B of the system B To focus on.

  Therefore, in the degenerate mode of FIG. 5, contrary to the degenerate mode of FIG. 4, the access control unit 12B of the system B becomes active, and the multiple line control is performed for the PON lines 4A and 4B of both systems A and B. As a result, the access control unit 12A of the system A becomes a standby state and enters a non-communication state in which communication frames are not communicated.

[Operation method of station side equipment]
As described above, in the present embodiment, in response to a command from the operator, either one of the access control units 12A and 12B performs multiple line control for controlling access to the PON lines 4A and 4B of both systems A and B. It is possible to cause the station side apparatus 2 to execute a degeneration mode in which the other access control units 12A and 12B do not communicate communication frames.

  Therefore, for example, the operator of the PON system can change the computer program and change the programmable program components such as FPGA and MPU included in the access control units 12A and 12B that are in the standby mode during the degeneration mode. You can restart after the change. Note that the “change” of the computer program includes correction, addition, and deletion of the program.

  In this case, in the degeneration mode, the active access control units 12A and 12B perform the multiple line control for the PON lines 4A and 4B of the system A and the system B. Therefore, during the period of the degeneration mode, the standby access control unit 12A , 12B, the computer program can be updated without stopping the data transfer in the station apparatus 2.

As another operation method of the station-side device, power supply to the standby access control units 12A and 12B may be stopped or suppressed during the degeneration mode.
In this case, the power consumption in the access control units 12A and 12B of the station side apparatus 2 can be reduced as compared with the case where power is supplied to both the access control units 12A and 12B of the systems A and B as usual.

In the degenerate mode, the active access control units 12A and 12B perform uplink multiple access control for a larger number of home side devices 3 than in the normal mode, so that the home side devices 3 than in the normal mode. The communication band will be reduced.
For this reason, it is preferable that the time zone for performing the degenerate mode is, for example, a time zone during the night when the traffic on the PON lines 4A and 4B is a predetermined value or less. In this case, it becomes possible to reduce the influence of a decrease in the communication band per home-side device 3 due to an increase in home-side devices 3 controlled by the active access control units 12A and 12B.

In the station side apparatus 2 of the present embodiment, as described above, the PON control unit 26 of the access control units 12A and 12B manages the LLID values so as not to overlap in both systems A and B, and for each LLID, The information necessary to maintain the link is shared with each other.
In addition, the PON control unit 26 of the access control units 12A and 12B uses the same clock generator to synchronize clocks when performing uplink multiple access control, so that the time stamp deviation between them is less than a predetermined value. Time synchronization is planned.

Therefore, in the station side apparatus 2 of this embodiment, the control subject of the uplink multiple access control based on MPCP is changed by switching from the normal mode to the degenerate mode, or conversely, switching from the degenerate mode to the normal mode. Even so, the logical link with the home-side apparatus 3 belonging to the PON lines 4A and 4B of both systems A and B is maintained.
For this reason, there is an advantage that it is possible to prevent an increase in the time during which communication is interrupted by automatically disconnecting the LLID every time the mode is switched.

[First Modification]
In the above-described embodiment, the degeneration control unit 20 may be configured to allow the logical link to be automatically disconnected by switching the operation mode of the station side device 2 by switching the route of both the switches 11 and 14. Good.
However, in such an implementation, the access control units 12A and 12B of the respective systems A and B have the PON control unit 26 before and after the degeneration control unit 20 switches both the switches 11 and 14, respectively. It is preferable to cancel the registration of the LLID in which the control subject changes.

  For example, when the operation mode of the station side device 2 is switched from the normal mode to the degenerate mode in which the system A is active and the system B is in the standby mode, the PON control unit 26 of the access control unit 12B of the system B Regardless of whether or not a deregistration request is received from the home side device 3 belonging to 4B, the deregistration may be transmitted uniformly to all the home side devices 3 belonging to the PON line 4B.

In this way, after the operation mode of the station side device 2 is switched to the degenerate mode, the home side device 3 belonging to the PON line 4B makes a register request to the PON control unit 26 of the access control unit 12A, and this request is triggered. Since the PON control unit 26 of the access control unit 12A newly assigns an LLID to the home side device 3 belonging to the PON line 4B, before switching the operation mode of the station side device 2 to the degenerate mode, It is not necessary to manage the LLID values used by the A and B PON control units 26 so as not to overlap.
Therefore, the degenerate mode can be realized relatively easily.

[Second Modification]
In the above-described embodiment, as a registration method of the home side apparatus 3 by the active access control units 12A and 12B, the upstream frame input source in the lower switch 14 is systematized for each discovery process during the execution period of the multiple line control. It is preferable to fix to one of the optical transmission / reception units 16A and 16B of A or the system B and execute the registration sequence of the home side apparatus 3 in the fixed state.

The reason is as follows. That is, the registration sequence of the home device 3 is performed according to a procedure in which the station side device 2 and the home device 3 exchange the next control frame.
1) The station side device 2 broadcasts a discovery gate.
2) The home side device 3 returns a register request to the station side device 2.
3) The station side device 2 transmits the register in which the LLID is described to the home side device 3.
4) The home side device 3 returns a register confirmation to the station side device 2.

  Therefore, for example, when the PON control unit 26 of the access control unit 12A of the system A is the subject of the registration sequence, if the upstream frame input source in the lower switch 14 is switched during the registration sequence, the home side device 3 (register request and register confirmation) cannot be received by the PON control unit 26 of the access control unit 12A, and the registration sequence of the home device 3 cannot be executed properly.

In this regard, if the optical transmission / reception units 16A and 16B are fixed for each discovery process and the registration sequence is executed, the same access control units 12A and 12B can appropriately execute the procedure of the registration sequence, and active access control is performed. Even during the period in which the units 12A and 12B are performing the multiple line control, the new home device 3 can be appropriately joined to the PON.
Further, in this case, the active access control units 12A and 12B can surely grasp whether the new home side apparatus 3 belongs to the PON of the A or B system.

[Third Modification]
In the above-described embodiment, the access control units 12A and 12B of the systems A and B have the transmission timing of the permitted uplink frame before the switching of the switches 11 and 14 by the degeneration control unit 20 in the uplink multiple access control according to MPCP. It is preferable to generate only those grants.

  More specifically, it is assumed that the grant generation time is t1, the switching time of the switches 11 and 14 is t2, the uplink frame transmission timing described in the grant is t3, and the switches 11 and 14 are configured to concentrate access control on the system A side. Assuming the case of switching, the PON control unit 26 of the access control unit 12B that is in the standby mode in the degenerate mode does not generate a grant and has t1 <t3 <t2 at the timing when t1 <t2 <t3. A grant is generated only for timing.

  The reason for this is that when the PON control unit 26 of the access control unit 12B that is in standby in the degenerate mode generates a grant at the timing of t1 <t2 <t3, the PON control unit 26 permits it before switching the switches 11 and 14. The uplink frame based on the granted grant may reach the station side device 2 after switching the switches 11 and 14, and may collide with another uplink frame that the PON control unit 26 of the active access control unit 12A has granted in the past. Because.

  In this regard, if the PON control unit 26 of the access control unit 12B that is in standby in the degenerate mode generates a grant only at the timing when t1 <t3 <t2, the uplink transmission as described above accompanying the switching to the degenerate mode is performed. A collision can be avoided in advance, and the transition to the degenerate mode can be performed appropriately.

[Fourth Modification]
In the above-described embodiment, the PON control unit 26 of the access control units 12A and 12B that is active in the degenerate mode allows the upstream frame to be permitted to the home-side apparatus 3 belonging to the same PON line 4A and 4B when performing multiple line control. It is preferable to schedule the uplink frame so that the transmission timings of the frames are as continuous as possible.

6 and 7 are sequence diagrams for illustrating the effect of the scheduling. In FIG. 6, a case where the active access control units 12A and 12B schedule uplink frames regardless of the ONU systems A and B is illustrated. FIG. 7 shows a case where uplink frames of the same systems A and B are continuously scheduled to schedule the uplink frames.
6 and 7, ONU1 and ONU3 belong to the PON line 4A of system A, and ONU2 belongs to the PON line 4B of system B.

In the example illustrated in FIG. 6, the OSU performs uplink frame scheduling so that the ONUs 1 to 3 perform uplink transmission in the order of ONU 1 (system A) → ONU 2 (system B) → ONU 3 (system A).
In this case, as shown in the uppermost part of FIG. 6, when the system types of the reports received from the ONUs 1 to 3 or the reports with data are arranged by the OSU, A → B → A → A → B → A → A → B → A, and the system type is switched 6 times in total.

Therefore, in the scheduling shown in FIG. 6, it is necessary to switch the lower switch 14 six times when a total of nine uplink frames are received.
However, in the scheduling in which the lower switch 14 is frequently switched as described above, the upstream bandwidth is unnecessarily compressed when the time overhead of switching the lower switch 14 is not small.

On the other hand, in the example shown in FIG. 7, the OSU is configured so that the ONUs 1 to 3 perform uplink transmission in the order of ONU 1 (system A) → ONU 3 (system A) → ONU 2 (system B), that is, the PON line. Uplink frame scheduling is performed so that the uplink transmission timings of system A belonging to 4A are continuous.
In this case, as shown in the uppermost part of FIG. 7, when the system types of the reports received from the ONUs 1 to 3 or the reports with data are arranged by the OSU, A → A → B → A → A → A → A → B → B, and the system type is switched three times in total.

Therefore, in the scheduling shown in FIG. 7, the switching of the lower switch 14 is completed three times when a total of nine uplink frames are received.
In this way, if the transmission timing of the upstream frame permitted to the home side devices 3 belonging to the same PON lines 4A and 4B is made continuous, the upstream frame scheduling is randomly performed without considering that, The number of times the lower switch 14 is switched within a predetermined time can be reduced. For this reason, there is an advantage that the loss of the upstream band accompanying the switching of the lower switch 14 can be reduced.

[Fifth Modification]
In the above-described embodiment, the case where the OSUs 2 constituting the OLT 1 each have the upper switch 11 is exemplified. However, the upper switch 11 is a redundant concentrator that multiplexes the upper side of each OSU 2 as shown in FIG. You may decide to comprise by 11a.
In this case, if all the functions of the upper switch 11 are performed by the concentrator 11a, the upper switch 11 is not required on the OSU 2 mounting board. However, the function of the upper switch 11 may be shared between the concentrator 11a and the OSU 2 mounting board.

[Sixth Modification]
In the above-described embodiment, a part of the function of the lower switch 14 may be incorporated in the access control units 12A and 12B. FIG. 9 is a block diagram showing an example of the implementation.
As shown in FIG. 9, the lower-level switch 14 of this modification includes internal switches 14R and 14T incorporated in the PON-side receiving unit 27 and the PON-side transmitting unit 28 in the access control units 12A and 12B, and the access control unit 12A. , 12B and an external switch 14C provided outside.

The internal switch 14R on the reception side has an input port IA for the system A and an input port IB for the system B, and the internal switch 14T on the transmission side has an output port OA for the system A and an output port for the system B. OB.
The external switch 14C has two output ports corresponding to the two input ports IA and IB of the internal switch 14R and two inputs corresponding to the two output ports OA and OB of the internal switch 14T as upper ports. Port.

The PON control units 26 of the systems A and B perform uplink multiple access control of either normal line control or multiple line control according to a command from the degeneration control unit 20. Here, paying attention to the access control unit 12A of the system A, the PON side transmission unit 28 of the control unit 12A, when the system A is the normal line control, from the output port OA of the internal switch 14T only, the external switch 14C. Download data to the corresponding port.
Further, the PON-side transmitting unit 28 of the access control unit 12A inputs the downlink data from the ports OA and OB of the internal switch 14T to the corresponding ports of the external switch 14C when the system A is controlled by a plurality of lines.

On the other hand, the external switch 14C puts the upstream data received from the optical receiving unit 30 of the system A into the input port IA of the internal switch 14R of the PON side receiving unit 27 when the system A is the normal line control.
Further, when the system A is controlled by a plurality of lines, the external switch 14C puts the upstream data received from the optical receiver 30 of the system A into the input port IA of the internal switch 14R of the PON side receiver 27, and The uplink data received from the B optical receiver 30 is input to the input port IB of the internal switch 14R of the PON side receiver 27.

Then, the PON control unit 26 of the system A is configured so that the reception processing in the PON side reception unit 27 for the upstream data input from the input ports IA and IB of the internal switch 14R does not compete with each other. Perform time division multiplexing control. For the access control unit 12B of the system B, the same processing as that of the system A is performed.
In the modification of FIG. 9, the internal switch 14T on the transmission side may be one port, and downlink data may be copied in the case of multiple line control.

  As shown in the modification of FIG. 9, when the operation mode of the station side device 2 is switched, the distribution processing (route selection) of the communication data to each system A, B is performed by the external switch 14C, and the multiple line control is performed. In this case, the time division multiplexing for the upstream data of both systems A and B may be performed by the internal switch 14R provided inside the access control units 12A and 12B.

[Other variations]
The embodiment disclosed this time (including the above-described modifications) is illustrative in all respects and not restrictive. The scope of the right of the present invention is not the embodiment described above, but includes all modifications within the scope equivalent to the configurations described in the claims.
For example, in the above-described embodiment, the access control units 12A and 12B of both systems A and B can execute the multiple line control. For example, only one access control unit 12A executes the multiple line control. The other access control unit 12B may execute only normal line control.

In this case, since only the access control unit 12A performs the multiple line control, the access control unit 12A does not enter standby in the degenerate mode.
Accordingly, the computer program cannot be updated with the access control unit 12A in the standby state, but the power supply to the access control unit 12B can be stopped or suppressed to reduce the power consumption, thereby reducing the power consumption. Therefore, there is a certain effect when the degenerate mode is used.

In the above-described embodiment, two systems of PON lines 4A and 4B are connected to the station side device 2, and the access control units 12A and 12B and the optical transmission / reception units 16A and 16B correspond to the two systems A and B, respectively. These are provided in pairs, but there may be three or more of these.
For example, in the case of the station side apparatus 2 having the three systems (systems A to C) of the PON lines 4A to 4C, the optical transmission / reception unit 16C of the system C is distributed to the access control units 12A and 12B of the systems A and B. A degenerate configuration in which the access control unit 12C is in a non-communication state, and the optical transmission / reception units 16B and 16C in the systems B and C are attributed to the access control unit 12A in the system A, and the access control units 12B and 12C are simultaneously in a non-communication state. Various degenerate configurations such as the degenerate configuration can be defined.

  As described above, assuming the station side apparatus 2 that controls the PON lines 4A to 4C of three or more systems, the “first” PON line, the access control unit, and the active device in the degenerate mode are active. There may be a plurality of optical transceivers. Similarly, there may be a plurality of “second” PON lines, access control units, and optical transmission / reception units that are in standby in the degenerate mode.

1 Station side equipment (OLT)
2 Station side equipment (OSU)
3. Home unit (ONU)
4A PON line 4B PON line 11 Upper switch 12A Access control unit 12B Access control unit 14 Lower switch 15 Optical transmission / reception control unit 16A Optical transmission / reception unit 16B Optical transmission / reception unit 19 Management interface 20 Degeneration control unit 25 Management table 26 PON control unit

Claims (16)

A station side device that constitutes a PON system with a plurality of home side devices,
A first optical transmission / reception unit connectable to the first PON line;
A second optical transmission / reception unit connectable to the second PON line;
A first access control unit capable of executing normal line control, which is uplink multiple access control for the first PON line, and multiple line control, which is the uplink multiple access control for the first and second PON lines; ,
A second access control unit capable of executing normal line control which is the uplink multiple access control for the second PON line;
An upper switch provided on the upper side of the both access control units;
A lower switch provided between the both access control units and the two optical transmission / reception units;
A degeneration control unit capable of switching both the switches as in the following (a) and (b);
A station side device characterized by comprising:
(A) The output destinations of the downstream frames to the first and second PON lines input to the upper switch are concentrated on the first access control unit, and the downstream frames input to the lower switch from the first access control unit The output destination is distributed to the first and second optical transmission / reception units.
(B) Concentrate output destinations of uplink frames input from the first and second optical transmission / reception units to the lower switch in the first access control unit. The station-side apparatus according to claim 1, wherein the degeneration control unit can further switch the both switches as in the following (c) and (d).
(C) The output destination of the downstream frame to the first and second PON lines input to the upper switch is distributed to the first and second access control units, and the first and second access control units are transferred to the lower switch. The output destinations of the input downlink frames are set in the first and second optical transmission / reception units, respectively.
(D) Cause the first and second access control units to set the output destinations of the upstream frames input from the first and second optical transmission / reception units to the lower switch.   The first access control unit has a management table that holds a logical link identifier for the first PON line and a logical link identifier for the second PON line so that values do not overlap. The station apparatus according to claim 1, wherein the multiple line control is performed using a logical link identifier held in the management table.   The first access control unit acquires information necessary for maintaining a logical link from the second access control unit, and stores the information in advance in the management table for each logical link identifier. The station side apparatus according to claim 3, wherein the multiple line control is performed.   The station-side device according to claim 4, wherein the first access control unit performs the multi-line control using a clock synchronized with the second access control unit.   The station according to claim 4 or 5, wherein the first access control unit performs the multi-line control using a time stamp whose deviation from a time stamp used by the second access control unit is a predetermined value or less. Side device.   7. The first and second access control units cancel registration of a logical link identifier in which a control subject of the uplink multiple access control changes before and after the degeneration control unit switches both the switches. The station side apparatus of any one of these.   In the multiple line control, the first access control unit fixes an upstream frame input source in the lower switch to either the first or second optical transmission / reception unit for each discovery process. The station side apparatus of any one of Claims 1-7 which perform the registration sequence of a side apparatus.   The said 1st and 2nd access control part produces | generates only the grant whose transmission timing of the upstream frame to permit is before switching of both said switches by the said degeneracy control part. The station side apparatus of description.   The said 1st access control part schedules the said uplink frame so that the transmission timing of the uplink frame permitted to the said home side apparatus which belongs to the same said PON line in the said multiple channel control may continue. 10. The station-side device according to any one of 9 above. A method of switching and operating an operation mode of a station side apparatus to which at least two PON lines are connected, wherein the switchable operation modes include the following (x) and (y): Operation method of station side equipment.
(X) Normal mode in which the first access control unit performs uplink multiple access control for the first PON line, and the second access control unit performs the uplink multiple access control for the second PON line. (Y) First And a degenerate mode in which the first access control unit performs multi-line control, which is the uplink multiple access control for the second PON line, and does not allow communication frames to be communicated to the second access control unit   The operation method of the station side apparatus of Claim 11 which performs the change of the computer program with respect to the programmable component contained in the said 2nd access control part, and the restart after the change during the period of the said degeneration mode. The operation method of the station side apparatus according to claim 11, wherein power supply to the second access control unit is stopped or suppressed during the degeneration mode.   The operation method of the station side device according to any one of claims 11 to 13, wherein the degeneration mode is executed in a time zone in which traffic on the first and second PON lines is equal to or less than a predetermined value. An access control apparatus that performs uplink multiple access control,
A management table that holds logical link identifiers for identifying home devices;
A PON control unit that performs the uplink multiple access control using a logical link identifier held in the management table,
The PON control unit overlaps the logical link identifier for the first PON line normally managed by itself and the logical link identifier for the second PON line normally managed by another access control device. In the management table, and using the logical link identifier held in the management table, the multi-line control which is the uplink multiple access control for the first and second PON lines is performed. Access control device. Said station side apparatus capable operation method according to 請 Motomeko 11,
A plurality of home-side devices respectively connected to the first and second PON lines connected to the station-side device;
PON system characterized by comprising.

Images